The present invention relates to the gas phase catalytic production of styrene from 4-vinylcyclohexene.
Styrene is an important monomer useful in the production of polymers such as polystyrene. Owing to its important commercial value, effective processes for the production of styrene are highly sought.
An example of a process useful for the production of styrene is disclosed in U.S. Pat. No. 4,165,441. This patent discloses a process for the gas phase oxidative dehydrogenation of 4-vinylcyclohexene in the presence of a catalyst containing tin, antimony, and oxygen. The patent describes the use of water as a component in the feed stream containing 4-vinylcyclohexene. The molar ratio of water to 4-vinylcyclohexene in the feed stream is about 8.5:1. While the patent reports reasonable yields with a variety of catalysts containing tin, antimony, and oxygen, the examples only report data for runs up to a few hours of continuous production of styrene. It is known, however, that under the conditions employed in U.S. Pat. No. 4,165,441, the half-life of the catalyst is quite low. Thus, the process disclosed in U.S. Pat. No. 165,441 results in poor yields after an undesirably short amount of time when the process is run continuously. Similarly, the process disclosed in U.S. Pat. No. 4,165,441 requires frequent stoppage of the process to regenerate the catalyst. Hence, to enable effective commercial use of such a process, it is desirable to increase significantly the half-life of said catalyst and thereby provide a process capable of being used to commercial advantage.